1. Technical Field
The invention relates to a motor drive device and an image-forming device including the same.
2. Related Art
A conventional motor drive device for controlling a brushless DC motor is provided with a control circuit that performs digital control and a motor drive circuit that drives the motor in response to instructions from the control circuit. For example, Japanese Patent Publication No. 2001-61297 discloses an image-forming device having a speed determination circuit and a motor lock circuit provided within an application-specific integrated circuit (ASIC) chip. The ASIC produces a signal for a motor driver IC having a Hall-effect amplifier and a phase-switching circuit, thereby driving the brushless DC motor.
However, in the conventional motor drive device, a phase-switching circuit is provided within the motor drive circuit, as disclosed in Japanese Patent Publication No. 2001-61297. Therefore, the circuit configuration tends to be complicated, which may lead to an increase in size and cost of the device. When the motor drive circuit is mounted on a circuit board with other analog servo circuitry, the analog servo circuitry may be affected by heat generated by the motor drive circuit, leading to unstable control.